Site description
This reserve is located in north-western Swaziland, between the border towns of Bulembu and Ngwenya, along the eastern Drakensberg escarpment of southern Africa. The western boundary of the reserve forms the border with South Africa, abutting on Songimvelo Nature Reserve (IBA ZA017). Havelock Mine and Swaziland Plantations own the land north of the reserve and the eastern boundary runs close to the main Mbabane/Pigg’s Peak road. Within the reserve lie some of the oldest sedimentary rocks known, c.3,600 million years in age. The site is dominated by the rugged mountains of the Silotfwane, Mgwayiza and Ngwenya ranges, including two of Swaziland’s highest peaks, Ngwenya (1,837 m) and Silotfwane (1,680 m), as well as its highest waterfall, Malolotja Falls. Steep valleys and gorges cut into this mountain escarpment, while deep river valleys and gentle rolling grassland plains dominate the adjacent landscape.Sour highland grassveld covers the gently undulating hills and slopes interspersed with narrow drainage lines. Scrubby vegetation occurs patchily along clear, fast-flowing mountain streams. Mountain slopes contain thornveld, and there are a few Protea bushes on Ngwenya Mountain. The valley slopes contain savanna trees and shrubs. Forests are restricted to the more mesic valleys. Also present are rocky outcrops, as well as open rock cliffs that form part of the Drakensberg escarpment.

Key biodiversity
See Box and Tables 2 and 3 for key species. To date c.290 species have been recorded in the reserve. Malolotja holds suitable habitat for many important grassland-dependent species. This is the only reserve in Swaziland where Hirundo atrocaerulea occurs regularly. Pairs breed along the eastern boundary of the reserve near the entrance gate. The rolling primary grassland is restricted to the eastern sector of the reserve; further west the geology changes and the topography becomes steeper, more dissected and unsuitable for this species. Geronticus calvus breeds regularly at Malolotja Falls, and irregularly at a small number of satellite sites. They are often observed foraging in burnt grassland. Grus paradisea was formerly an altitudinal migrant in Swaziland; three pairs bred in Malolotja Vlei, She Mine area and Mhlangamphepha Valley. However, this species is now extinct in Swaziland, since there has been no sign of it since 1994 despite several searches (Monadjem et al. in prep.).Francolinus levaillantoides, Neotis denhami and Sarothrura affinis are breeding residents that are virtually restricted, in Swaziland, to Malolotja Nature Reserve. Other grassland species of concern include Vanellus melanopterus, Turnix hottentotta and Schoenicola brevirostris. Francolinus shelleyi is a fairly common resident in the foothills of the Malolotja Valley.The moist vleis hold Circus ranivorus and Tyto capensis, as well as Balearica regulorum formerly, but this species has now been extinct in Swaziland for over a decade (Monadjem et al. in prep.). The riverine and Afromontane forests in the reserve hold Tauraco corythaix, Lioptilus nigricapillus, Cossypha dichroa, Telophorus olivaceus and Serinus scotops. Two previously unknown species, Zoothera gurneyi (a first for Swaziland) and Cercotrichas signata, were found in the isolated Mgwayiza mist-belt forest north of the Nkomati river in 1998 (this forest is the site of a proposed chert mine). Geocolaptes olivaceus and Saxicola bifasciata are found on exposed rocky grassland slopes where Monticola explorator occurs as a winter visitor. The small patches of Protea bushes on Ngwenya Mountain hold a few Promerops gurneyi. Buteo oreophilus has been recorded nearby and may frequent the reserve as a non-breeding migrant.

Non-bird biodiversity: The cycads Encephalartos lanatus (Rare), E. paucidentatus (VU) and E. laevifolius (EN) are protected here. All three species are extremely rare and localized, and much sought after by collectors for cultivation. The small tree, Cassipourea swaziensis (EN), virtually restricted to western Swaziland, occurs in the reserve. Among mammals, Ourebia ourebi (LR/cd), confined in eastern South Africa and Swaziland to the grassland areas of the high-altitude escarpment, occurs here, Connochaetes gnou (LR/cd) and Damaliscus dorcas phillipsi (LR/cd) have been reintroduced to the reserve, and the southern African endemics Myosorex varius, Suncus infinitesimus, Amblysomus hottentotus and Pelea capreolus also occur.